1. Field of the Invention
The present invention relates to a color display device using liquid crystals.
2. Description of the Prior Art
Currently used in the most common method for displaying color in a liquid crystal display are color filters for the three primary colors--red, blue, and green--which are provided for each of the picture elements in a liquid crystal display cell. Specifically, three picture elements are constructed to form one unit, in which the color to be displayed--red, blue, and green--in the respective picture element is predetermined, and, making use of the fact that the human eye is unable to distinguish the respective color elements, the method provides a total color harmony of the three colors in the display through the picture elements. For example, when the color to be displayed is white, the red, blue, and green picture elements are all displayed. Because the human eye is unable to differentiate between the respective three picture elements, the total of the three colors appears as white.
In this method, the color filters are usually provided inside the liquid crystal display cell. This is because, if they were provided on the outside of the liquid crystal display cell, the view would change according to the viewing angle.
This method has some drawbacks that the structure is complicated because one filter is provided for one picture element, that because three picture elements--red, blue, and green--are combined as one unit, the display is rather coarse, and that because the intensity of light for each color must be even, the thickness of the filters is not necessarily uniform, resulting in that the thickness of the liquid crystal layer is uneven.
In the case of TN type liquid crystal a slight variance in the layer thickness has no effect on the display, but in the case of a ferroelectric liquid crystal, even a slight variance in the thickness of the layer will affect the display.
Accordingly, there are existing problems to be solved in conventional liquid crystal display devices with respect to two features of picture quality and simplification of the manufacturing process.